Monitoring Discharge Pressure on Concrete Mix Load

ABSTRACT

Disclosed are method and system for treating concrete in mixing drums of delivery vehicles having automated rheology (e.g., slump) monitoring systems programmed to dose fluids into concrete based on the monitored rheology. The present invention takes into account a Revolution-To-Discharge value (“RTD”) which reflects drum rotations needed to move concrete towards and through the mixing drum opening from which concrete is discharged, and also takes into consideration a Volume-Per-Revolution-Upon-Discharge (“VPRUD”) value which reflects the relation between the rate of discharge and rheology (e.g., slump) of concrete upon discharge. The invention is especially useful for reclaiming concrete in the drum after delivery and can confirm rheology based upon peak (maximum) discharge pressure. The present inventors found surprisingly that discharge pressure readings are useful for recalibrating automated rheology monitoring systems as well as for reporting and/or treating the remainder concrete.

FIELD OF THE INVENTION

The present invention relates to manufacturing of concrete, and moreparticularly to a system and method for treating concrete and/orreporting volume of concrete in a delivery vehicle mixing drum, andespecially with regard to concrete remaining in the mixing drum afterprior partial discharge or delivery.

BACKGROUND OF THE INVENTION

Bobrowski et al. taught that concrete remaining in the mixing drum ofdelivery trucks can be reclaimed for use by adding a retarding admixtureto stabilize the remainder concrete (See U.S. Pat. No. 4,964,917),optionally adding new concrete to the remainder (See U.S. Pat. No.5,203,919), and then using an accelerator just before re-using thereclaimed concrete (See U.S. Pat. No. 5,247,617).

Hines et al. taught that the amount of admixture to be dosed into thetruck returning from delivery can be calculated based on remaining loadsize and temperature of the concrete (See U.S. Pat. No. 6,042,258) andthat admixture dosing could be done on an automated basis (See U.S. Pat.No. 6,042,259).

The present inventors believe that prior art methods for calculating theconcrete load remaining in the truck after delivery are neithersufficiently accurate nor practically convenient. For example, it isknown to weigh the mixing truck on a weight scale before and afterdelivery (See e.g., U.S. Pat. No. 5,752,768; U.S. Pat. No. 6,123,444;U.S. Pat. No. 8,020,431; and GB 2392502), but weight can vary due toimprecision of the scale and various other factors (such as fluctuationof fuel tank and other fluid tank levels).

It is also known to estimate concrete discharged from the drum bycounting mixing drum rotations required to discharge a known volume ofconcrete. A typical concrete mixing drum has a pair of mixing bladesmounted on the inner drum wall, helically arrayed about the rotationalaxis of the drum. The blades thus function in the manner of anArchimedes' screw device. When the drum rotates in the “charge” (loadingor mixing) direction, the blades push concrete towards the closed end ofthe drum; and, when the drum rotates in the “discharge” direction, theblades push concrete towards and through an opening located at theopposite end of the drum. The concrete expelled through the drum openingcan then be guided by a chute to the desired spot where it is to beplaced. Often, the load will not be fully discharged, and the remainderwill be returned in the mixing drum to the plant or moved to anotherplacement location; and the remaining volume of concrete would typicallybe measured by rough visual approximation or by subtracting a roughestimate of the discharged amount from the amount of the original load.

To this point, the current practice of estimating the remainder load hasbeen premised upon the assumption that the amount of concrete dischargedfrom the drum can be calculated based upon the number of drum rotationsrequired to expel the concrete from the drum. This relation is mentionedin various patents, including U.S. Pat. No. 5,752,768 of Assh (Col. 18,line 40 et seq.), U.S. Pat. No. 8,020,431 of Cooley, and U.S. Pat. No.8,118,473 of Compton. However, the present inventors believe thisassumption is predicated on a the underlying assumption that the numberof rotations required to bring concrete to the drum opening is constantfrom load to load, and further that the amount of discharge for eachdrum rotation is also constant from load to load.

In U.S. Pat. Nos. 6,611,755, 6,892,131, and 7,489,993, Coffee et al.disclosed that Begin Pour and End Pour events (i.e., charging anddischarge) can be based upon, among other approaches, the number of drumrotations in the discharge direction, and that the truck can be weighedas part of determining amounts of concrete remaining in the drum afterthe End Pour event. The number of discharge revolutions for the BeginPour event is hitherto assumed or estimated to be 1 or 2 drumrevolutions, regardless of the load size of the concrete. While this maybe adequate for determining Begin Pour and End Pour events, the presentinventors believe that a novel system and method are required forachieving high accuracy in calculating the amount of concrete remainingin the drum after partial discharge.

SUMMARY OF THE INVENTION

In surmounting the disadvantages of the prior art which hithertoattempts to measure the amount of concrete as a static amount presumedto be expelled from the delivery truck concrete mixing drum in a fixedamount per fixed rotation of the drum, the present inventors provide anovel, convenient, and highly accurate method for treating concreteand/or reporting volume of concrete in the mixing drum.

The invention involves a highly accurate determination of the amount ofconcrete in the mixing drum and takes into account (i) theRevolution-To-Discharge value (RTD) which is the number of drumrotations required to move the concrete load into discharge position,and this is primarily a function of load size; and (ii) theVolume-Per-Revolution-Upon-Discharge value (VPRUD) which reflects theamount of concrete removed per drum revolution after the load beginsdischarging, and this is primarily a function of concrete rheology(e.g., slump) at discharge. RTD and VPRUD values are illustrated byFIGS. 1 and 2, respectively, and further discussed hereinafter.

The invention is particularly useful for treating concrete remaining inthe drum after a portion of the concrete has been discharged, such aswhen the vehicle has returned from a delivery, or when the vehicle ismoved from one pouring event to another pouring event (on anotherconstruction site or even at the same site).

An exemplary method of the present invention for treating concreteand/or reporting volume of concrete in a mixing drum comprises: (A)determining load size of concrete remaining in the mixing drum afterprior partial discharge of concrete from the drum, by employing anautomated rheology monitoring system having a computer processor unit(“CPU”), said CPU being connected to at least one sensor for measuringrheology of concrete in the mixing drum, said CPU being connected to asensor for determining the number of mixing drum rotations, said CPUbeing programmed to calculate load size (“LS”) based on the followingformula: LS=OLS−(RR−RTD)*VPRUD, wherein “OLS” represents the originalload size of concrete in the mixing drum before said previous partialdischarge of concrete from the drum; “RR” represents the number of drumrotations in the discharge direction required for said previous partialdischarge; “RTD” represents the Revolutions-To-Discharge value whichcorresponds to the number of mixing drum rotations in the dischargedirection required to commence discharge of concrete from the mixingdrum, the number of mixing drum rotations being a function of OLS; and“VPRUD” represents the Volume-Per-Revolution-Upon-Discharge value whichcorresponds to discharge rate of the concrete in terms of amount ofconcrete discharged for each mixing drum rotation in the dischargedirection (as the discharge rate of concrete is a function of therheology of the concrete at the time of discharge); the OLS, RR, RTD,and VPRUD being stored in CPU-accessible location and employed by a CPUin calculating load size of the concrete remaining in the drum afterprevious partial load discharge; and (B) treating and/or reporting thevolume of the concrete remaining in the mixing drum, based on theremaining load size determined in accordance with the formula providedabove, said treating and/or reporting comprising (i) adding to saidconcrete in the mixing drum a fluid comprising water, chemicaladmixture, or both, the amount of said fluid added determined in respectof said determined concrete load size within the mixing drum; (ii)adding to said concrete in the mixing drum an amount of fresh concretewhich is determined in respect of said determined concrete load sizewithin the mixing drum; (iii) reporting the determined concrete loadsize on an electronic display; (iv) reporting the determined concreteload size to the dispatch center; (v) reporting the determined concreteload size to a customer; or (vi) performing some or all of any of theforegoing (i) through (v).

An exemplary system of the invention for treating concrete and/orreporting volume of concrete in a mixing drum remaining after priorpartial discharge, comprises: a computer processing unit (CPU)electrically or wirelessly connected to at least one sensor formeasuring rheology of concrete in the mixing drum, at least one sensor(e.g., speed, accelerometer) for measuring the rotational speed of themixing drum, and a CPU-accessible location having software instructionsfor the CPU to achieve the steps A and B as previously described above.

In preferred methods and systems of the present invention, slump of theconcrete is measured by ascertaining the peak pressure in the dischargeport of the hydraulic system that rotates the mixing drum duringdischarge, and the slump value can be employed in the above-describedformula (such as for computing the Volume-Per-Revolution-Upon-Dischargevalue or “VPRUD”), whereby the concrete volume in the drum iscalculated. The present invention provides an accurate and convenientmethod and system for treating the concrete (e.g., dosing with fluid orfurther concrete additions) or for reporting concrete volume or otherproperties. The present inventors have surprisingly discovered that this“peak discharge pressure” provides an accurate indication of the slumpof the concrete. This slump (or other rheological) value at dischargecan be stored in CPU-accessible memory and used for various purposes,such as for calibrating the correlation data between a data set ofrheology values and corresponding data set of fluid dosage additions(water, chemicals) when the mixing drum is rotated in the chargedirection (wherein the dosage additions have been correlated withrheology state achieved by adding a given dosage or amount).

For example, if the CPU monitors concrete slump and instructs that adosage of chemical admixture (e.g., superplasticizer) be added into themixing drum to increase the slump to a target slump desired at finaldelivery (pour), the automated concrete monitoring system can monitorthe peak discharge pressure and compare this to prior correlations(i.e., in CPU-accessible memory or storage) between peak dischargepressure values previously measured (using sensor for measuring thehydraulic pressure to rotate drum in discharge direction) anddischarged-concrete slump values previously measured (using a standardslump cone); and the CPU can be programmed to recalibrate the automatedrheology monitoring system wherein slump is monitored by sensingrotation of the drum in the charge (mixing) direction and chemicaladmixture is dosed into the drum during mixing to reach a desired slumplevel.

An exemplary method of the present invention for monitoring rheology ofconcrete, comprises: in an automated concrete rheology monitoring systemhaving a computer processing unit (CPU) connected electrically orwirelessly to a plurality of sensors configured for monitoringconditions on a concrete delivery vehicle having a mixing drum forconcrete, including a sensor for monitoring discharge pressure on themixing drum, performing the following steps: monitoring dischargepressure of a concrete load discharged from the concrete mixing drum;comparing the monitored peak discharge pressure of the dischargedconcrete load with CPU-accessible database wherein peak dischargepressure values correspond to concrete rheology values; and reporting arheology value of the concrete discharged based on the peak dischargepressure as monitored. Preferably, the rotational speed of the drum ismonitored, and preferably kept between 1-5 revolutions per minute atdischarge.

The reporting step may comprise one or more of the following: (a)indicating said rheology value on a monitor screen and/or ticket; (b)providing an indication on a monitor screen and/or ticket confirmingwhether or not peak discharge pressure monitored corresponds to arheology condition that coincides with target rheology specified for theconcrete; or (c) performing (a) and (b).

The peak discharge pressure monitored for the discharge load can be usedin the calculation of remaining load size (LS), in accordance with theabove-described formula, LS=OLS−(RR−RTD)*VPRUD, wherein “OLS” representsthe original load size of concrete in the mixing drum before saidprevious partial discharge of concrete from the drum; “RR” representsthe number of drum rotations in the discharge direction required forsaid previous partial discharge; “RTD” represents theRevolution-To-Discharge value which corresponds to the number of mixingdrum rotations in the discharge direction required to commence dischargeof concrete from the mixing drum, said number of mixing drum rotationsbeing a function of concrete load size in the mixing drum; and “VPRUD”represents the Volume-Per-Revolution-Upon-Discharge value whichcorresponds to discharge rate of the concrete in terms of amount ofconcrete discharged for each mixing drum rotation in the dischargedirection, said discharge rate of concrete being a function of therheology of the concrete at the time of discharge; and said OLS, RR,RTD, and VPRUD being stored in CPU-accessible location and employed by aCPU in calculating load size of the concrete remaining in the drum aftera prior partial discharge.

An exemplary system of the present invention for monitoring concrete ina delivery vehicle mixing drum comprises: an automated concrete rheologymonitoring system having a computer processing unit (CPU) connectedelectrically or wirelessly to a plurality of sensors for monitoringconditions on a concrete delivery vehicle having a mixing drum,including sensor for monitoring charge pressure, sensor for monitoringdischarge pressure, and sensor for monitoring rotational speed of themixing drum; a set of CPU-accessible correlation values wherein peakdischarge pressure is correlated with rheology of concrete discharged;and instructions for the CPU to monitor discharge pressure for rotatingthe mixing drum in the discharge direction and for reporting a rheologyvalue of the concrete discharged from the mixing drum based on the peakdischarge pressure as monitored.

For example, reporting can be performed by having the system transmit,such as to the dispatch center or customer, data to confirm the slump ofthe concrete at discharge, or to initiate an alarm if the concrete slumpas monitored at discharge (using the peak pressure value) is found bythe system to differ from the target slump that was previously specifiedfor delivery. If slump at delivery has been found by the system todepart from the target slump specified by the customer by 10%, 15%, 20%or more, the system can alert the ready-mix producer, the driver, thedispatch center (if different from the ready-mix plant), and/or theready-mix customer of this fact, so that corrective steps can be takenif necessary or the load can be returned if corrective steps cannot betaken to restore the concrete to the target rheology condition specifiedby the ready-mix producer or customer.

The present inventors further discovered that discharge pressuremonitoring is useful for confirming when concrete has been completelyunloaded from the mixing drum. Thus, an exemplary method for determiningwhen discharge of concrete from a delivery vehicle mixing drum iscomplete, comprises: monitoring discharge pressure for rotating themixing drum in the direction of discharge, by employing a sensor whichis in electrical or wireless combination with an automated concretemonitoring system having a computer processing unit (CPU); sensing whendischarge pressure falls below a predetermined discharge pressure valuestored into CPU-accessible memory or storage, the predetermineddischarge pressure value corresponding with an empty mixing drum state;and reporting completion of the concrete discharge from the mixing drum.For example, where the rotation rate of the drum in discharge directionis 2-5 revolutions per minute (RPM), the predetermined dischargepressure value is preferably between 100-400 RPM, and more preferablybetween 150-250 RPM.

The above-described methods and systems of the invention thereforeprovide surprising new capabilities for the concrete industry to monitorand to ensure consistency and high quality in the concrete beingdelivered to the customer.

Further advantages and features may be discussed hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages and features of the present invention may be morereadily comprehended when the following detailed description ofpreferred embodiments is considered in conjunction with appendeddrawings wherein:

FIG. 1 is a graphic illustration of a “Revolution-To-Discharge” (RTD)value which the inventors deem to indicate the number of mixing drumrevolutions, as a function of load size, needed for commencing concretedischarge from the delivery truck mixing drum opening; and

FIG. 2 is a graphic illustration of a“Volume-Per-Revolution-Upon-Discharge” (VPRUD) value which the inventorsdeem to indicate the rate of concrete discharge, in terms of cubic yardsof concrete for each revolution of the mixing drum, as a function of theconcrete slump at the time of discharge from the mixing drum, whereinslump of discharged concrete is measured in inches;

FIG. 3 is graphic illustration of actual volume of concrete dischargedper drum revolution compared to predicted volume of concrete dischargedper drum revolution;

FIGS. 4A, 4B, and 4C are graphic illustrations of a concrete mix duringloading and unloading, whereby each of the respective properties of drumrotation speed in both directions of loading and unloading (See FIG.4A), charge pressure (See FIG. 4B), and discharge pressure (See FIG. 4C)are plotted along their respective vertical axes as a function of mixingdrum rotations as plotted along the horizontal axis; and

FIG. 5 is a graphic illustration of a correlation between slump ofconcrete (inches) and the maximum (peak) discharge pressure (pounds persquare inch) for rotating the mixing drum in the discharge direction.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The term “concrete” as used herein will be understood to refer tomaterials including a cement binder (e.g., Portland cement optionallywith supplemental cementitious materials such as fly ash, granulatedblast furnace slag, limestone, or other pozzolanic materials), water,and aggregates (e.g., sand, crushed gravel or stones, and mixturesthereof), which are effective for forming a building or civilengineering structure when in a hardened state. The concrete optionallycontains one or more chemical admixtures, such as plasticizingadmixtures (including water-reducing agents, such as lignosulfonates, orsuperplasticizers (e.g., polycarboxylate comb polymers), set retarders,set accelerators, air entrainers, air detrainers, strength enhancers,pigments, colorants, fibers for plastic shrinkage control or structuralreinforcement, and the like.

Conventional chemical admixtures are contemplated for use in the presentinvention. When incorporated into left over or remainder concrete whichis deemed suitable for re-use, such an admixture is sometimes referredto as a “stabilizing” or “hydration stabilizing” or “hydrationcontrolling” admixture. Such admixtures can include set retarders,water-reducers, agent, or mixture of these. Lignosulfonates, forexample, are water-reducers having retarding characteristics.

A stabilizing admixture in the form of a ready-to-use aqueous solutionis available from Grace Construction Products, Massachusetts, USA, underthe RECOVER® trade name. This is often used as a stabilizing admixturefor left over concrete and is believed to be suitable for purposes ofthe invention.

As mentioned in the background section, ready-mix delivery truckstypically have a pair of mixing blades mounted on the inner wall of themixing drum, and somewhat helically arrayed around the rotational axisof the drum. The blades act in screw-like fashion to push concretetowards the closed end of the drum when rotated in the “charge” (orloading-mixing) direction; the blades otherwise push concrete towardsand through an opening at the opposite end of the drum when it rotatedin a “discharge” direction. The rotational axis of the mixing drum isusually slanted with respect to level ground, such that the opening ofthe drum, which usually overlaps the rotational axis of the drum, islocated at a somewhat higher level than the closed end, such that theblades must push the concrete upwards against the inclined inner wall ofthe rotating drum towards the opening through which the concrete isexpelled. The principles of the present invention may be applied toready-mix trucks which have more or fewer blades, but trucks having twoblades appear are the most prevalent in the industry. In any event,concrete delivery vehicles having rotatable mixing drums with theabove-described orientation of mixing blades are contemplated for use inthe present invention.

The mixing drums for ready mixed concrete trucks are rotated by ahydraulic pump and motor. The pump is connected to the PTO of the engineof the vehicle and the motor is connected to the mixing drum. In orderto operate the drum in either the charge or discharge direction, thehydraulic motor is connected to the chambers associated with charge andwith discharge. Test ports are typically available for mounting pressuresensors for monitoring hydraulic pressure on both the charge anddischarge side. Generally, when the mixing drum is rotated in the chargedirection, the pressure of the hydraulic fluid in the charge portincreases. When the mixing drum is rotated in the discharge direction,pressure of the hydraulic fluid in the discharge side of the motorincreases. The present invention involves mounting sensors formonitoring pressure on the charge port (“charge pressure”) and sensorsfor monitoring pressure on the discharge port (“discharge pressure”).

Concrete trucks are commonly equipped with water tanks connected by ahose line directed into the drum opening. In this manner, fluid can bedispensed into the drum under air pressure in the tank or by pump. Suchtank dispensing devices are disclosed in U.S. Pat. No. 4,544,275, U.S.Pat. No. 7,842,096 and U.S. patent application Ser. No. 11/955,737, forexample. When a chemical admixture tank is the fluid conveyed on thetruck, the tank is typically connected to the same hose line used fordischarging water into the drum. The chemical admixture may be dispensedinto the water line under air pressure or by tank to the pump. This isexemplified in U.S. Pat. No. 7,730,903. Alternatively, chemicaladmixtures and water may be dispensed using different lines into themixing drum.

The terms “rheology” as used herein is intended to include slump, slumpflow, DIN flow, yield stress, thixotropy, and other rheologicalcharacteristics of plastic concrete. “Slump” is used herein as a matterof convenience, as systems for monitoring concrete slump are becomingrecognized in the industry, wherein the force or energy required torotate the concrete drum (such as hydraulic pressure) is correlated withslump of the concrete in the drum (whereby slump is measured by using astandard slump cone test for a given sample of concrete), and theeffects of water and chemical admixture, respectively, on the concreteslump can also be monitored and the relationship stored in computermemory for later use in adjusting or controlling the slump of theconcrete by administering the dose as determined by the computerprocessing unit.

These relationships are described by some of the references as may bevarious described herein. It is thus possible that other rheologicalproperties of the concrete, other than or in addition to slump, can becorrelated with pressure and/or other forces required to rotate thedrum; although “slump” and “pressure” (hydraulic) will be used as themost convenient concepts for explication of the present invention.

For example, automated concrete slump monitoring systems on concretedelivery vehicles (e.g., ready mix trucks) are disclosed in U.S. Pat.Nos. 6,611,755; 6,892,131; and 7,489,993 of Coffee et al. (owned by thecommon assignee hereof) may be suitable for modified use in the presentinvention. Other exemplary automated concrete slump monitoring systemsare believed to be suitable for modified use in the present invention,such as U.S. Pat. No. 6,484,079 and Ser. No. 09/845,660 of Buckelew.These references are again incorporated herein by reference.

In particular, Buckelew disclosed providing a sensor in the hydraulicline for rotating the truck mixing drum in the charging direction, aswell as a separate sensor in the hydraulic line for rotating the truckmixing drum in the discharging direction.

The term “charge pressure” will be used herein to refer to the(hydraulic) pressure in the pump-motor hydraulic system to rotate themixing drum in the loading/charging/mixing direction; while “dischargepressure” will be used herein to refer to refer to the (hydraulic)pressure in the pump-motor hydraulic system to rotate the drum in thedirection to discharge or expel concrete from the drum.

It is believed that a number of exemplary embodiments of the inventionmay be practiced using commercially available automated concrete mixmonitoring equipment with modifications as would be apparent in view ofthe teachings disclosed herein. Automated slump monitoring systems areavailable from Verifi LLC, West Chester, Ohio, and Cambridge, Mass.,USA, under the trade name VERIFI®, and these are believed to be suitablefor modification in accordance with the teachings of the presentinvention as disclosed herein.

The term “automated slump monitoring system” will be used to refer tocomputer processor unit (CPU) devices which are effective for monitoringat least one rheological property of concrete in mixing drums. This isaccomplished by measuring hydraulic, electrical, or other forcesrequired for rotating the mixing drum, and for correlating the measuredforce value with the slump/rheological value; and optionally fordispensing water or chemical additives to adjust or to control theslump/rheological value.

As summarized above, an exemplary method of the present invention fortreating concrete and/or reporting volume of the concrete in a mixingdrum, such as concrete remaining after prior partial discharge ofconcrete from the drum, comprises two basic steps, which are labeled “A”and “B” which are further described below:

Step (A) involves determining load size of concrete, and thismethodology is applicable to determination of concrete remaining in themixing drum after delivery or any other prior partial discharge ofconcrete from the drum. This load size (LS) can be computed bysubtracting, from the number of drum rotations in the dischargedirection required for expelling or discharging the concrete from thedrum, the “Revolutions-To-Discharge” value, which is the number of drumrotations in the discharge direction required for moving the concretematerial up to the drum opening, and then multiplying this difference bythe “Volume-Per-Revolution-Upon-Discharge value,” which corresponds tothe rate of concrete discharged for each drum rotation in the dischargedirection as a function of rheology (e.g., slump) at the time ofdischarge. This amount of concrete discharged is subtracted from theoriginal load size (OLS) that was loaded into the mixing drum at thebatch plant.

The above calculation is preferably accomplished by use of an automatedrheology (e.g., slump) monitoring system having a computer processorunit (“CPU”) wherein the CPU is connected to at least one sensor formeasuring rheology (e.g., slump) of the concrete in the mixing drum, andthe CPU is connected to a sensor for determining the number of mixingdrum rotations, and the CPU is programmed to calculate remainder loadsize (“LS”) based on the following formula:

LS=OLS−(RR−RTD)*VPRUD

wherein “OLS” represents the original load size of concrete in themixing drum before said previous partial discharge of concrete from thedrum (wherein OLS may be inputted at the batch plant, either manually bythe batch plant manager, or electronically by the automated batchingsystem); “RR” represents the number of drum rotations in the dischargedirection required for the previous partial discharge of concrete fromthe mixing drum; “RTD” represents the Revolution-To-Discharge valuewhich corresponds to the number of mixing drum rotations in thedischarge direction required to commence discharge of concrete from themixing drum, the number of mixing drum rotations being a function ofconcrete load size in the mixing drum; and “VPRUD” represents theVolume-Per-Revolution-Upon-Discharge value which corresponds todischarge rate of the concrete in terms of amount of concrete dischargedfor each mixing drum rotation in the discharge direction, the dischargerate of concrete being a function of the slump of the concrete at thetime of discharge; and each of the OLS, RR, RTD, and VPRUD values arestored in CPU-accessible location (e.g., memory or storage file on thetruck or located at a remote location) and employed by CPU incalculating load size of the concrete remaining in the drum afterprevious partial load discharge.

Step “B” involves treating the concrete and/or reporting a volume of theconcrete contained in the mixing drum (or otherwise remaining in thedrum after a partial discharge or after delivery) based on thecalculation done in Step (A), wherein remaining load size is determinedbased on LS=OLS−(RR−RTD)*VPRUD as set forth above, and the exemplarytreating step comprises: (i) adding to said concrete in the mixing druma fluid comprising water, chemical admixture, or both, the fluid addedbeing in an amount determined in respect of said determined concreteload size; (ii) adding to the concrete in the mixing drum an amount offresh concrete which is determined in respect of the determined concreteload size within the mixing drum; (iii) reporting said determinedconcrete load size on an electronic display; (iv) reporting thedetermined concrete load size to dispatch center; (v) reporting thedetermined concrete load size to a customer; or (vi) performing some orall of any of the foregoing (i) through (v).

For example, if step B(i) is pursued, the monitoring system CPU can beprogrammed to add a predetermined amount of cement dispersant admixture(e.g., superplasticizer) into the mixing drum based on the remainingload size as calculated in step (A). Accordingly, the system CPU can beprogrammed to access a database wherein admixture amounts have beenpreviously correlated with rheology changes, such that an appropriateamount of admixture can be added into the mixing drum such that theconcrete can be treated so as to obtain a desired or target rheology(e.g., slump). Automated slump monitoring systems may, for example, beprogrammed by inputting the desired or target rheology into the CPU.

As another example, if B(ii) is selected and the remainder concrete isdeemed to be suitable for re-cycling, then the remainder amount can bedetermined in accordance with step (A) and a supplemental concrete canbe added up to a predetermined or desired new load amount.

As a further example, if B(iii) is selected, the monitoring system CPUcan be instructed to report the remainder amount of concrete in themixing drum as calculated in step (A), such as by transmitting anindication or value corresponding to the remainder amount and/or thecalculated prior discharged amount to a monitor screen of a personalcomputer, laptop, or hand-held device in possession of the ready-mixproducer or dispatch center, the customer, architect, or person locatedat a remote location. A person working in the dispatch center could, forexample, determine whether any remaining concrete is suitable for use ona different construction site.

A system for treating concrete and/or reporting volume of concrete in amixing drum remaining after prior partial discharge, comprising: acomputer processing unit (CPU) electrically or wirelessly connected toat least one sensor for measuring rheology of concrete in the mixingdrum, at least one sensor (e.g., speed, accelerometer) for measuring therotational speed of the mixing drum, and a CPU-accessible locationhaving software instructions for the CPU to achieve steps A and B, aspreviously set forth above. In preferred embodiments, the CPU iselectrically or wirelessly connected to at least one sensor formeasuring the (hydraulic) pressure for rotating a concrete mixing drumin the charge direction, and at least one sensor for measuring the(hydraulic) pressure for rotating the concrete mixing drum in thedischarge direction.

Once the remainder concrete amount is calculated in step (A) and theconcrete is treated and/or reported as provided in step (B), furtherexemplary methods and systems of the invention can further comprisedeterminations by the system CPU, based on the remainder concrete slump,temperature, and batch mixture components, other jobsites where theremainder concrete can be utilized. The temperature of the concrete inthe mixing drum can be monitored, and the information regarding thebatch components can be either inputted at the batch plant and/orautomatically downloaded from the batching system at the plant.

Also as summarized previously, the calculation of remainder concreteamount involves consideration in step (A) of the RTD value, an exampleof which is provided in FIG. 1, and the VPRUD value, an example of whichis provided in FIG. 2. The drawings in FIGS. 1 and 2 are discussed infurther detail as follows.

In FIG. 1, the Revolution-To-Discharge value (RTD) suggests the delayfactor and is expressed in terms of the number of drum rotationsrequired for a particular concrete load size to be pushed by the mixingblades upwards along the inner drum wall and towards the drum openingthrough which the concrete is expelled (discharged) from the mixingdrum. In other words, the RTD value is the number of rotations needed tostart removing concrete material from the mixing drum. No concrete comesout of the mixing drum until this number of revolutions is reached.Hence, the RTD value is a function of load size.

In FIG. 2, the “Volume-Per-Revolution-Upon-Discharge” (VPRUD) value isused to determine how much concrete volume comes out of the drum whenthe drum is rotated in the discharge direction. In this situation, thepresent inventors discovered that the rate at which the concrete isdischarged is a function primarily of the slump of the concrete (withsome effect from the geometry or shape of the drum which contains theconcrete) at the time of discharge.

By subtracting the RTD value from the number of discharge revolutions(RR) and multiplying this difference by the VPRUD value, the presentinventors surprisingly discovered that they could accurately determinethe amount of concrete discharged from the drum. When the volume ofdischarged concrete was predicted based on the foregoing calculations,the present inventors found that their predictions were highly accuratewhen compared to data points obtained empirically using concretedischarged with known slump as measured by standard slump cone. Hence,the predicted discharge volumes per drum rotation are compared to actualdischarge volumes per drum rotation, and these values are illustrated inFIG. 3.

FIG. 3 confirms the high accuracy afforded by the present invention interms of the ability to calculate the volume of unloaded concrete, and,hence, the volume of concrete remaining in the mixing drum.

The present inventors discovered that monitoring the discharge pressureprovides an indication of when the concrete is completely dischargedfrom the drum (as will be further discussed hereinafter), but moresignificantly reveals a surprising and unexpected property of theconcrete during its last moments in the mixing drum. As mentioned above,the “discharge pressure” value can be measured from a sensor installedin the hydraulic line used for forcing the drum to rotate in a dischargedirection; this is different from the sensor installed in a line forhydraulically forcing rotation of the drum in the charging/mixingdirection. The present inventors discovered that there is a correlationbetween peak (or maximum) discharge pressure and the slump of thedischarged concrete, and that this correlation exists independent of thesize of the load being discharged. This surprising discovery occurredwhen the inventors examined the data illustrated in FIGS. 4A-4C and 5.

FIGS. 4A, 4B, and 4C each graphically illustrate, for the same concreteloading and unloading operation on a delivery truck, the drum speed androtational direction with respect to drum speed (See FIG. 4A), thecharge pressure (See FIG. 4B), and the discharge pressure (See FIG. 4C),each as a function of drum rotation as indicated along the horizontalaxis of each of the respective graphs in FIGS. 4A-4C, which are arrangedto represent states during loading and discharge.

The rotational speed of the mixing drum is indicated in FIG. 4A alongthe left vertical axis in terms of revolutions per minute (“RPM”) inincrements of 5 RPM, and this is provided for the charging direction asshown in the upper half (positive value) of FIG. 4A as well as for thedischarging direction as shown in the lower half (negative value) ofFIG. 4A. As indicated at 1 in FIG. 4A, the mixing drum is in chargingmode, as concrete is loaded and mixed, and drum speed is held constantat about 17 RPM. As indicated for this same period in FIG. 4B, thecharge pressure is high (about 1,500 PSI); while for this same period inFIG. 4C, the discharge pressure is low (about 225 PSI).

As shown at 2 in FIG. 4A, the mixing drum reverses direction and goesinto discharge mode (approximately by 273^(rd) drum revolution). Duringdischarge mode between the 273^(rd) and 289^(th) drum revolution, thedrum speed is nearly constant (about 4.6-5.2 RPM) as indicated by therelatively flat portion of the graph. During this phase, the chargepressure drops to a very low point as shown in FIG. 4B; while thedischarge pressure climbs very rapidly as shown in FIG. 4C.

Peak discharge pressure is designated at 3 in FIG. 4C. As will befurther explained hereinafter, the present inventors were surprised tofind that this peak or maximum discharge pressure reflected a consistentrelationship with rheology (e.g., slump) of the concrete beingdischarged from the mixing drum. This relationship is best seen when therotational speed of the discharging mixing drum is kept as constant aspossible, such as between 1 and 5 or 6 revolutions per minute.

By the 285^(th) rotation, discharge pressure begins to decrease rapidly(as shown in FIG. 4C). At the 289^(th) rotation, drum speed anddischarge pressure are increased as the last remaining concrete isexpelled from the drum. The mixing drum can then be returned to theplant for the next load and set into charge mode for this purpose (asshown at 5 in FIG. 4A).

It is further evident from FIG. 4 that drum speed has an effect on bothdischarge and charge pressure, even when the rheology and load size arenot changing. Thus, a sensor for measuring drum speed can be provided.

FIG. 5 illustrates graphically the correlation that was surprisingdiscovered by the present inventors between the peak (maximum point) ofdischarge pressure and the slump of the discharged concrete. Therotation speed of the drum in discharge mode should preferably be keptconstant between 1-6 RPM, and, more preferably, about 2-4 RPM foroptimum results. The results in FIG. 5 were based on data obtained from97 deliveries using three different fleets of concrete mixing truckshaving automated slump monitoring systems, and these results demonstratea relationship hitherto unknown in the industry. It was unexpected andsurprising that this relationship can be used to determine what theslump of concrete was at discharge by measuring peak pressure duringdischarge of the concrete.

In view of this discovery, the inventors set forth other aspects oftheir invention as follows.

In exemplary methods and systems of the invention, the rheology ofconcrete discharged from mixing drum is determined based on peakdischarge pressure and the drum rotation speed as measured duringdischarge of concrete from the drum. The automatic rheology (e.g.,slump) monitoring system CPU can be programmed with instructions or toaccess a database containing (prior) correlations between values of peakdischarge pressure and rheology (slump) values (as graphicallyillustrated for example in FIG. 5), and the peak discharge pressure fora given load is then measured (at known constant drum rotation speed indischarge direction). The CPU is also programmed to issue a report, forexample, in the form of an alarm (such as where slump measured atdischarge differs substantially by a predetermined difference value fromthe target slump that was previously specified into the system CPU fordischarge). For example, the predetermined difference value may be 5%,10%, 15%, 20%, 25%, or more, which may be set as desired by theready-mix producer or by the dispatch center.

An exemplary method of the invention for determining rheology ofconcrete, comprises: in an automated concrete rheology monitoring systemhaving a computer processing unit (CPU) connected electrically orwirelessly to a plurality of sensors configured for monitoringconditions on a concrete delivery vehicle having a mixing drum forconcrete, including sensors for monitoring charge pressure and dischargepressure on the mixing drum, performing the following steps: in anautomated concrete rheology monitoring system having a computerprocessing unit (CPU) connected electrically or wirelessly to aplurality of sensors configured for monitoring conditions on a concretedelivery vehicle having a mixing drum for concrete, including a sensorfor monitoring discharge pressure on the mixing drum (and optionally andpreferably also including sensor for monitoring charge pressure andsensor for measuring rotational speed of the mixing drum), performingthe following steps: monitoring discharge pressure of a concrete loaddischarged from the concrete mixing drum; comparing the monitored peakdischarge pressure of the discharged concrete load with CPU-accessibledatabase wherein peak discharge pressure values correspond to concreterheology values; and reporting a rheology value of the concretedischarged based on the peak discharge pressure as monitored.

The reporting can comprise one or more of the following steps: (a)indicating the rheology value on a ticket and/or monitor screen (of apersonal computer, laptop, or hand-held device); (b) providing anindication on a monitor screen and/or ticket confirming whether or notpeak discharge pressure monitored corresponds to a rheology conditionthat coincides with target rheology specified for the concrete; or (c)performing both steps (a) and (b).

The reporting can also additionally include an alarm which is activatedon the truck and/or at the dispatch center, if the slump at deliverypour is confirmed, using measurement of peak discharge pressure andcomparing the corresponding rheology (slump data), to exceed (by apredetermined amount or percentage) a target slump that was earlierspecified by input into the system CPU.

As mentioned in the summary section, the system (apparatus or device)could be installed on a ready-mix concrete delivery truck in the form ofcommercially available automated slump monitoring system (e.g., VERIFI®control systems) modified in accordance with the teachings of thepresent invention. CPU-accessible correlation values, wherein peakdischarge pressure is correlated with slump of concrete discharged, canbe kept in CPU-accessible memory or storage, either located on thetruck, or at a remote location (such as dispatch center).

In view of the teachings herein, the system may be modified to reportremainder concrete amounts (if any) and/or the rheology of the concreteat discharge, using values or symbols on a monitor screen, such as thatof a personal computer, laptop, or hand-held device (e.g., Apple®IPhone® or IPad® devices) to display slump or other rheology property ofthe concrete as discharged from the mixing drum, or to display theremainder amount of concrete. Such monitor screen can be accessible tothe customer as well as to the ready-mix producer.

Other exemplary methods and systems of the invention can be configuredsuch that, based on the use of the CPU-accessible correlation valueswherein peak discharge pressure is correlated with slump or otherrheology property of the concrete discharged, as well as the use of theabove-described method for determining the amount of concrete dischargedfrom the mixing drum, namely, the calculation of concrete dischargedusing the formula (RR−RTD)*VPRUD (wherein the VPRUD factor can becomputed based on peak discharge pressure as monitored (and correlatedwith a slump value), and calculating remaining concrete load bysubtracting the discharged amount from the original load size, it ispossible to generate a report regarding volume and/or rheology conditionof the concrete, such as through the issuance of a ticket (paperdocument) or a readout display on a portable electronic screen,regarding amount of concrete delivery (discharged) and slump of concreteat the time of delivery.

Due to the accuracy of using peak discharge pressure monitoring tomeasure rheology of the concrete, as suggested by the curve in FIG. 3(which compares actual volume of concrete discharged per drum revolutionand predicted volumes of concrete discharged per drum revolution), thepresent inventors believe it is possible to confirm accuracy of and evento recalibrate an automated rheology (e.g., slump) monitoring system.

Thus, a further exemplary automated concrete rheology monitoring systemor method of the invention, wherein said automated concrete rheologymonitoring system further comprises CPU-accessible data comprisingcorrelation values between concrete rheology measured prior to dischargebased on charge pressure and during discharge based on dischargepressure, and determining whether to update the correlation valueinvolving charge pressure and concrete rheology if the two said concreterheology values differ by more than a pre-determined amount.

Still further exemplary embodiments comprise using CPU-accessible datahaving correlation values between concrete rheology and fluid additionswhich are added into the concrete mix to alter said rheology, andwherein peak discharge pressure is measured and used to calibrate thecorrelation values between concrete rheology (as monitored by the systembased on charge pressure when the drum is rotating in the mixing/loadingdirection) and the fluid additions which are added into the concrete mixto alter the rheology of the concrete (and the effect of such fluidadditions are correlated with rheology as monitored by the system basedon charge pressure when the drum is rotating in the mixing/loadingdirection).

The aforementioned methods and systems of the invention, in view of theforegoing description of advantages and features, can be employed toaccomplish a number of functionalities and to provide visual indications(in the form of tickets or larger printouts or monitored displays)confirming that a particular function has occurred or confirming theextent to which it has occurred. For example, exemplary methods andsystems can be modified for various beneficial uses, including thefollowing:

-   -   (a) As described above, one can use remaining load size to        calculate slump; or, conversely, calculate remaining load size        or discharged amount based on peak discharge pressure, by having        the CPU perform calculations based on stored CPU-accessible        correlation values wherein peak discharge pressure is correlated        with slump of concrete discharged.    -   (b) The Revolution-To-Discharge value (RTD) or        Volume-Per-Revolution-Upon-Discharge value (VPRUD) as discussed        above can be used to confirm the initial load size received in        the mixing truck from the batch plant. Thus, for a complete        discharge, the CPU should calculate the load size discharged        based on (RR−RTD)*VPRUD; and this should be equal to the        original load size (OLS) as indicated on a batching ticket or        data transmission from the concrete batching plant. Thus,        methods and systems of the invention can provide an indication,        in the form of a ticket or data transmission to a monitor        screen, that the total amount of concrete delivered equaled the        original load size.    -   (c) Calculation of the remaining load size may be used to        calculate and/or manage the amount of water or chemical        admixture to be added to the concrete in the mixing drum, and        such admixtures may include one or more of any, some, or all of        the following: water-reducer (e.g., superplasticizer) admixture,        set retarding admixture, accelerator admixture), air entraining        admixture.    -   (d) The CPU can be instructed such that alarms, monitor screen        symbols, alerts, or other indications can be transmitted, such        as by wireless communication, to the dispatch center, the        foreman at the construction site, supervisory architect, the        driver of the truck or other trucks, etc., that concrete is        available (e.g., remaining) in the mixing drum, the volume as        well as the slump of the available or remaining concrete.    -   (e) The CPU can be instructed to provide a separate ticket        (paper or electronic) from dispatch software which confirms the        remaining quantity of concrete.    -   (f) The CPU can also be instructed to issue an invoice (paper or        electronic) to the customer for disposal of returned concrete        (i.e., remainder concrete left over in the truck after return        from delivery).    -   (g) The CPU can also be instructed to determine whether        remainder concrete can be re-used based on one or more of the        following factors taken into consideration by the CPU: the time        since initial batching or loading at the concrete plant, the        number of drum revolutions the initial batching or loading,        temperature of concrete, quantity of water added to concrete,        quantity and type of chemical admixture added to the concrete,        the design strength of the concrete, the water-to-cement ratio,        and other factors.    -   (h) Where it is determined that the remainder concrete is        suitable for re-use, the CPU can be programmed to calculating        the quantity of one or more of cement, sand, coarse aggregate,        water, and admixture to be added to the remainder to obtain a        second batch of concrete which meets desired slump and        compressive strength targets.    -   (i) The CPU in the automated slump monitoring system can also be        programmed to measure or estimate one or more properties,        including air content, unit weight, water added to the drum        after batching, and using this information to revise the        computation of original load size, calculated discharge amounts,        and/or calculated remainder amounts after partial discharge.        This can be accomplished by providing a means for user to input        manually an air content or unit weight test result, or an        automated means of measuring air content such as those known in        the art.    -   (j) The CPU can be programmed such that remaining concrete, if a        selected minimum load size is detected, and the current slump is        detected as being too high, to provide an audible and/or visual        alarm so that the driver knows that there is a risk that        transporting the load could give rise to sloshing and hence        spillage of concrete from the drum.    -   (k) The CPU can be programmed to determine the relationship        between slump, load size, hydraulic pressure, and drum rotation        speed for load sizes different from those used in the original        calibration, wherein a rate of slump change from begin to end of        loading is selected from −1 in to 0 in. per minute.    -   (l) The systems and methods of the present invention can be        calibrated by using a load cell mounted on one or more trucks of        substantially similar geometry; or, conversely, the present        invention can be used to check the accuracy of load cells that        are currently in use.    -   (m) As explained elsewhere in this specification, the present        inventors believe that slump can be replaced with other        rheological values including slump flow, DIN flow, or others,        such that the calculation of Remaining Load Size (LS) can be        calculated based on the LS−(RR−RTD)*VPRUD wherein the        Volume-Per-Revolution-Upon-Discharge value (VPRUD) is based on        discharge rate as a function of the rheology value at the time        of discharge.

Other exemplary methods of the present invention for determiningrheology (e.g., slump) of concrete comprise: in an automated concreterheology monitoring system having a computer processing unit (CPU)connected electrically or wirelessly to a plurality of sensorsconfigured for monitoring conditions on a concrete delivery vehiclehaving a mixing drum for concrete, including sensors for monitoringcharge pressure and discharge pressure on the mixing drum, providingCPU-accessible correlation values wherein peak discharge pressure iscorrelated with rheology of concrete discharged; and (i) providing anindication of a concrete property based on rheology of concretedischarged as determined by said CPU, (ii) treating the concrete in themixing drum based on calculations by the CPU involving the determinedrheology of concrete in the mixing drum based on measurement of peakdischarge pressure, or (iii) performing both (i) and (ii).

In further exemplary methods, step (ii) further comprises treating theconcrete in the mixing drum based on calculations by the CPU involvingthe determined rheology of concrete in the mixing drum based onmeasurement of peak discharge pressure, wherein the treated concrete isconcrete remaining in the mixing drum after previous partial discharge,and the amount of remaining concrete is determined by employing anautomated rheology monitoring system having a computer processor unit(“CPU”), the CPU being connected to at least one sensor for monitoringpressure for rotating the mixing drum, and the CPU being connected to asensor for determining the number of mixing drum rotations, the CPUbeing programmed to calculate load size (“LS”) based on the followingformula: LS=OLS−(RR−RTD)*VPRUD wherein “OLS” represents the originalload size of concrete in the mixing drum before said previous partialdischarge of concrete from the drum; “RR” represents the number of drumrotations in the discharge direction required for said previous partialdischarge; “RTD” represents the Revolutions-To-Discharge value whichcorresponds to the number of mixing drum rotations in the dischargedirection required to commence discharge of concrete from the mixingdrum, said number of mixing drum rotations being a function of concreteload size in the mixing drum; and “VPRUD” represents theVolume-Per-Revolution-Upon-Discharge value which corresponds todischarge rate of the concrete in terms of amount of concrete dischargedfor each mixing drum rotation in the discharge direction, the dischargerate of concrete being a function of the rheology of the concrete at thetime of discharge; and OLS, RR, RTD, and VPRUD being stored inCPU-accessible location and employed by a CPU in calculating load sizeof the concrete remaining in the drum after previous partial loaddischarge.

In further exemplary methods, the automated concrete rheology monitoringsystem comprises CPU-accessible data values based on correlationsbetween concrete rheology and fluid additions which are added into theconcrete mix to alter said rheology, and further wherein peak dischargepressure is measured and used to calibrate the correlation betweenconcrete rheology and fluid additions which are added into the concretemix to alter said rheology.

An exemplary system of the invention for determining rheology ofconcrete, comprises: an automated concrete rheology monitoring systemhaving a computer processing unit (CPU) connected electrically orwirelessly to a plurality of sensors for monitoring conditions on aconcrete delivery vehicle having a mixing drum, including sensor formonitoring pressure on the mixing drum in the charge direction andsensor for monitoring pressure on the mixing drum in the dischargedirection (and preferably having sensor for monitoring rotational speedof the mixing drum); CPU-accessible correlation values wherein peakdischarge pressure is correlated with rheology of concrete discharged;and the CPU is instructed to calculate rheology of concrete contained ina mixing drum based on the CPU-accessible correlation values and toprovide a report (of volume of concrete in the mixing drum or otherwiseinitiate an alarm if concrete condition or status departs from a targetcondition or status) of a concrete property based on rheology ofconcrete discharged as determined by operation of the CPU, and/ortreating the concrete in the mixing drum based on calculations by theCPU involving the determined rheology of concrete in the mixing drum(e.g., such as by adding a dose of chemical admixture based on thedetermined rheology of concrete in the mixing drum).

The present inventors believe that monitoring of discharge pressure hasnot, until the present invention, been considered as useful forconfirming concrete volume on the delivery truck. They have discoveredthat the discharge pressure can be used for confirming when concrete hasbeen completely unloaded from the drum. Thus, an exemplary method of thepresent invention for determining when discharge of concrete from adelivery vehicle mixing drum is completed, comprises: monitoringdischarge pressure for rotating the mixing drum in the direction ofdischarge, by employing a sensor which is in electrical or wirelesscombination with an automated concrete monitoring system having acomputer processing unit (CPU); sensing when discharge pressure fallsbelow a predetermined discharge pressure value stored intoCPU-accessible memory or storage, said predetermined discharge pressurevalue corresponding with an empty mixing drum state; and reportingcompletion of the concrete discharge from the mixing drum.

For example, where the rotation rate of the drum in discharge directionis 2-5 revolutions per minute (RPM), the predetermined dischargepressure value is preferably between 100-400 RPM, and more preferablybetween 150-250 RPM.

In further exemplary embodiments, the number of mixing drum revolutionsis monitored from start to finish of discharge of a concrete load, andthe monitored number of drum revolutions is employed in revising orconfirming accuracy of CPU-accessible data, including the Revolutions toDischarge value (“RTD”) which corresponds to the number of mixing drumrotations in the discharge direction required to commence discharge ofconcrete from the mixing drum; and theVolume-Per-Revolution-Upon-Discharge value (“VPRUD”) which correspondsto discharge rate of the concrete in terms of amount of concretedischarged for each mixing drum rotation in the discharge direction.Both the RTD and VPRUD values were previously explained above.

The principles, preferred embodiments, and modes of operation of thepresent invention have been described in the foregoing specification.The invention which is intended to be protected herein, however, is notto be construed as limited to the particular forms disclosed, sincethese are to be regarded as illustrative rather than restrictive.Skilled artisans can make variations and changes without departing fromthe spirit of the invention.

1. (canceled)
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 13. A method for determining rheology ofconcrete, comprising: in an automated concrete rheology monitoringsystem having a computer processing unit (CPU) connected electrically orwirelessly to a plurality of sensors configured for monitoringconditions on a concrete delivery vehicle having a mixing drum forconcrete, including a sensor for monitoring discharge pressure on themixing drum, performing the following steps: monitoring dischargepressure of a concrete load discharged from the concrete mixing drum;comparing the monitored peak discharge pressure of the dischargedconcrete load with CPU-accessible database wherein peak dischargepressure values correspond to concrete rheology values; and reporting arheology value of the concrete discharged based on the peak dischargepressure as monitored.
 14. The process of claim 13 wherein saidreporting comprises one or more of the following steps: (a) indicatingsaid rheology value on a monitor screen and/or ticket; (b) providing anindication on a monitor screen and/or ticket confirming whether or notpeak discharge pressure monitored corresponds to a rheology conditionthat coincides with target rheology specified for the concrete; or (c)performing (a) and (b).
 15. The process of claim 13 further comprisingtreating concrete remaining in the concrete mixing drum after partialconcrete load discharge, the load (“LS”) being computed by the CPU basedon the formula, LS=OLS−(RR−RTD)*VPRUD, wherein “OLS” represents theoriginal load size of concrete in the mixing drum before said previouspartial discharge of concrete from the drum; “RR” represents the numberof drum rotations in the discharge direction required for said previouspartial discharge; “RTD” represents the Revolution-To-Discharge valuewhich corresponds to the number of mixing drum rotations in thedischarge direction required to commence discharge of concrete from themixing drum, said number of mixing drum rotations being a function ofconcrete load size in the mixing drum; and “VPRUD” represents theVolume-Per-Revolution-Upon-Discharge value which corresponds todischarge rate of the concrete in terms of amount of concrete dischargedfor each mixing drum rotation in the discharge direction, said dischargerate of concrete being a function of the rheology of the concrete at thetime of discharge; and said OLS, RR, RTD, and VPRUD being stored inCPU-accessible location and employed by a CPU in calculating load sizeof the concrete remaining in the drum after a prior partial discharge.16. The method of claim 13 wherein said automated concrete rheologymonitoring system further comprises CPU-accessible data comprisingcorrelations involving concrete rheology measured prior to dischargebased on charge pressure and during discharge based on dischargepressure, and determining whether to update the correlation involvingcharge pressure and concrete rheology if the two said concrete rheologyvalues differ by more than a pre-determined amount.
 17. (canceled) 18.(canceled)
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 20. The method of claim 16 further comprising:using CPU-accessible data having correlation values between concreterheology and fluid additions which are added into the concrete mix toalter said rheology, and wherein peak discharge pressure is measured andused to calibrate the correlation values between concrete rheology, asmonitored by the system based on charge pressure when the drum isrotating in the mixing/loading direction and the fluid additions whichare added into the concrete mix to alter the rheology of the concrete,the effect of such fluid additions being correlated with rheology asmonitored by the system based on charge pressure when the drum isrotating in the mixing/loading direction.
 21. The method of claim 13,wherein the rheology value is slump of concrete.
 22. The method of claim13, further comprising confirming that total amount of concretedischarged from the concrete mixing drum equaled the load size receivedin the mixing drum.
 23. The method of claim 15 wherein calculation ofthe remaining load size is used to calculate or manage the amount ofwater or chemical admixture to be added to the concrete in the mixingdrum, the admixtures being selected from the group consisting ofwater-reducer admixture, set retarding admixture, accelerator admixture,and air entraining admixture.
 24. The method of claim 15 wherein analarm, monitor screen symbol, alert, or other indication is transmittedto a dispatch center, foreman at the construction site, supervisoryarchitect, or driver of the truck or other trucks, corresponding toremaining concrete is available in the mixing drum and volume and slumpof the available remaining concrete.
 25. The method of claim 15 furthercomprising providing a paper or electronic ticket confirming quantity ofconcrete remaining in the mixer drum.
 26. The method of claim 15 furthercomprising providing a paper or electronic invoice for disposal ofconcrete remaining in the mixer drum.
 27. The method of claim 15 furthercomprising determining whether the concrete remaining in the mixer drumcan be re-used based on factors selected from time since initialbatching or loading at the concrete plant, the number of drumrevolutions since initial batching or loading, temperature of concrete,quantity of water added to concrete, quantity and type of chemicaladmixture added to the concrete, the design strength of the concrete,and water-to-cement ratio.
 28. The method of claim 13 wherein therheological value is slump flow.